This invention relates to a method of and apparatus for the display of conventional video signals at high field rate without complex pre-processing.
Conventional television systems, particularly those based on a field rate of 50 Hz, tend to suffer from flicker in large bright areas of the picture. Such flicker can be especially noticeable on large area displays, when it is perceived by the viewer's peripheral vision. Large area flicker can be reduced by increasing the field rate at the display; one simple method of achieving this would be to display each picture at twice the normal rate. This requires the use of a system of storage into which incoming signals are written and from which they are read twice over at twice the conventional scanning frequency. This simple method would remove large area flicker but would also provoke an annoying judder on moving objects, whose edges and fine detail would be portrayed as having discontinuous movement.
However, the display of moving parts of the picture in accordance with conventional scanning standards does not give rise to appreciable judder, assuming that the original scene was similarly scanned, e.g. in a conventional television camera. Moreover, the presence of movement will tend to prevent the perception of large area flicker.